/* 
 * File:   gstreamer_dome.c
 * Author: sean
 *
 * Created on 2012年4月3日, 下午9:18
 */

#include "gstreamer_dome.h"
//定义消息处理函数,

static gboolean bus_call(GstBus *bus, GstMessage *msg, gpointer data) {
    GMainLoop *loop = (GMainLoop *) data; //这个是主循环的指针，在接受EOS消息时退出循环
    switch (GST_MESSAGE_TYPE(msg)) {
        case GST_MESSAGE_EOS:
            g_print("End of stream\n");
            g_main_loop_quit(loop);
            break;
        case GST_MESSAGE_ERROR:
        {
            gchar *debug;
            GError *error;

            gst_message_parse_error(msg, &error, &debug);
            g_free(debug);
            g_printerr("ERROR:%s\n", error->message);
            g_error_free(error);
            g_main_loop_quit(loop);
            break;
        }
        default:
            break;
    }
    return TRUE;
}

int run_mp3(int argc, char *argv[]) {
    GMainLoop *loop;
    GstElement *pipeline, *source, *decoder, *sink; //定义组件
    GstBus *bus;

    gst_init(&argc, &argv);
    loop = g_main_loop_new(NULL, FALSE); //创建主循环，在执行 g_main_loop_run后正式开始循环

    if (argc != 2) {
        g_printerr("Usage:%s <mp3 filename>\n", argv[0]);
        return -1;
    }
    //创建管道和组件
    pipeline = gst_pipeline_new("audio-player");
    source = gst_element_factory_make("filesrc", "file-source");
    decoder = gst_element_factory_make("mad", "mad-decoder");
    sink = gst_element_factory_make("autoaudiosink", "audio-output");

    if (!pipeline || !source || !decoder || !sink) {
        g_printerr("One element could not be created.Exiting.\n");
        return -1;
    }
    //设置 source的location 参数。即 文件地址.
    g_object_set(G_OBJECT(source), "location", argv[1], NULL);
    //得到 管道的消息总线
    bus = gst_pipeline_get_bus(GST_PIPELINE(pipeline));
    //添加消息监视器
    gst_bus_add_watch(bus, bus_call, loop);
    gst_object_unref(bus);
    //把组件添加到管道中.管道是一个特殊的组件，可以更好的让数据流动
    gst_bin_add_many(GST_BIN(pipeline), source, decoder, sink, NULL);
    //依次连接组件
    gst_element_link_many(source, decoder, sink, NULL);
    //开始播放
    gst_element_set_state(pipeline, GST_STATE_PLAYING);
    g_print("Running\n");
    //开始循
    g_main_loop_run(loop);
    g_print("Returned,stopping playback\n");
    gst_element_set_state(pipeline, GST_STATE_NULL);
    gst_object_unref(GST_OBJECT(pipeline));
}